While writing the unit test cases for my
application I was getting the below mentioned exception during the execution of these test cases. Below is the complete exception trace :

java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.TaskInputOutputContext, but class was expected
at org.apache.hadoop.mrunit.internal.mapreduce.AbstractMockContextWrapper.createCommon(AbstractMockContextWrapper.java:59)
at org.apache.hadoop.mrunit.internal.mapreduce.MockMapContextWrapper.create(MockMapContextWrapper.java:77)
at org.apache.hadoop.mrunit.internal.mapreduce.MockMapContextWrapper.(MockMapContextWrapper.java:68)
at org.apache.hadoop.mrunit.mapreduce.MapDriver.getContextWrapper(MapDriver.java:167)
at org.apache.hadoop.mrunit.mapreduce.MapDriver.getContext(MapDriver.java:198)
at com.techidiocy.integratekeys.mapreduce.test.TestIntegrationKeysMapper.init(TestIntegrationKeysMapper.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:69)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:48)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:292)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

rdbms.exceptions.MappedDatastoreException: INSERT INTO “TABLE_PARAMS”

If you had read my previous post (Anatomy of a configuration file)where i
described the flow of the application
on which I was working . In the last
command of my morphline I wascreating the hive table using the avro schemawhich wascreated in the previous command.
As per the design of my application I
decided that i will store my avro schema file in the local file system instead of saving it on HDFS. Everything was working fine as expected , but things started breaking when my avro schema file contains more than 4000 characters. Below is the complete exception which I got while Hive table creation :

[This post will discuss about different types of write concern in MongoDB – Performance Vs Persistence.]
Controlling the writeoperations in an application is always an important aspect. Today almost all the frameworks that interact with datastores provide mechanism to let you know whether your write operation is successful or not. Now when we talk about in the context of MongoDB , it also provides you an ability called as Continue reading Types of Write Concern in MongoDB – Performance Vs Persistence→

While working on the array modifiers example
, I was trying to use the $sort
modifier with $each and $push modifier.In that example I added
an array of books to my original
document and was trying to sort it on the basis of one of the fields.As soon as I executed that method,i got our infamous IllegalArgumentException : Exception in thread “main” java.lang.IllegalArgumentException: can’t serialize class com.lotusmedia.mongo.models.Book (Can’t serialize class – MongoDB). Continue reading Can’t serialize class – MongoDB Illegal Argument Exception→